Process control systems, like those used in chemical, petroleum or other processes, typically include one or more process controllers and input/output (I/O) devices communicatively coupled to at least one host or operator workstation and to one or more field devices via analog, digital or combined analog/digital buses. The field devices, which may be, for example, valves, valve positioners, switches and transmitters (e.g., temperature, pressure and flow rate sensors), perform process control functions within the process such as opening or closing valves and measuring process control parameters. The process controllers receive signals indicative of process measurements made by the field devices, process this information to implement a control routine, and generate control signals that are sent over the buses or other communication lines to the field devices to control the operation of the process. In this manner, the process controllers may execute and coordinate control strategies using the field devices via the buses and/or other communication links communicatively coupling the field devices.
Information from the field devices and the controllers may be made available to one or more applications (i.e., software routines, programs, etc.) executed by the operator workstation (e.g., a processor-based system) to enable an operator to perform desired functions with respect to the process, such as viewing the current state of the process (e.g., via a graphical user interface), evaluating the process, modifying the operation of the process (e.g., via a visual object diagram), etc. Many process control systems also include one or more application stations. Typically, these application stations are implemented using a personal computer, workstation, or the like that is communicatively coupled to the controllers, operator workstations, and other systems within the process control system via a local area network (LAN). Each application station may execute one or more applications that perform campaign management functions, maintenance management functions, virtual control functions, diagnostic functions, real-time monitoring functions, safety-related functions, configuration functions, etc. within the process control system.
Process control systems typically include one or more operator terminals and/or application stations. These operator terminals and/or applications stations include one or more graphical interfaces to enable system operators to view current process-related algorithm information that may include functions and/or parameters, statistical information, historical process information, alarm information, campaign management information, execution information or, more generally, information provided by any or all of the applications associated with the process control system.
System designers or engineers create process control graphics to display process control information to system operators. This process control information may include process control parameter information and/or process control functions. For example, a process control visual object diagram may include a plurality of functional blocks, embedded composite objects, steps, and/or any other graphical object associated with portions of a process control system.